Caption: This set of Chandra images shows evidence for a light echo
generated by the Milky Way's supermassive black hole, a.k.a. Sagittarius
A*. Astronomers believe a mass equivalent to the planet Mercury was
devoured by the black hole about 50 years earlier, causing an X-ray
outburst which then reflected off gas clouds near Sagittarius A*.
Studying this light echo gives a crucial history of activity from the
black hole, and it also illuminates and probes the gas clouds near the
center of the Galaxy.

Scale: Close up images are 5 arcmin across; Full-field is 12.5 arcmin across.